


For Science!

by Sambergan



Category: Among Us (Video Game)
Genre: Alien Biology, Alien/Human Relationships, Anal Sex, Black is male, Breeding, Consensual but there is tension between the Crewmate and Impostor, Double Penetration, Enemies to Lovers, F/M, Interspecies Sex, Smut, Tentacle Sex, Vaginal Sex, White is Female, Xenophilia, Yeah this is Among Us porn, implied minor character death
Language: English
Status: Completed
Published: 2020-10-25
Updated: 2020-10-25
Packaged: 2021-03-08 22:40:50
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,000
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27183955
Author URL: https://archiveofourown.org/users/Sambergan/pseuds/Sambergan
Summary: Black is acting suspicious, and White has a need to find out why. She ends up getting way more than expected... but she isn't complaining.This is for science after all.---Smut Oneshot
Relationships: Black/White (Among Us), Crewmate/Impostor (Among Us)
Comments: 17
Kudos: 558





	For Science!

**Author's Note:**

> I wrote this cause I'm trash. I hope you enjoy!
> 
> The crewmates are intended to be regular humans and the impostors are obviously aliens. This is basically a fastburn enemies to lovers oneshot (and smut - actually, mostly just smut)
> 
> No warnings for this one since the sex is consensual and no graphic violence occurs, but game-typical minor character death is mentioned.

Black was acting suspicious.

Such things did not go unnoticed by White. After all, as the head of research and xenobiologist of The SKELD, it was her _job_ to be observant.

She didn’t miss how he seemed to bounce around from room to room despite never being seen traveling through the halls, nor how there was a sudden shift in his demeanor a few months back where his tasks magically managed to all be ‘finished’ before the rest of the crew woke up.

The fact that Yellow was found dead in the reactor right after an unexpected power outage, and that Black was the last ‘crewmate’ seen there with Yellow also didn’t help his case.

Yes, Black was _most definitely_ acting suspicious.

Any scientifically-minded astronaut was aware of the existence of Impostors: shapeshifting aliens that snuck aboard unsuspecting vessels to sabotage the crew from within. Their reasoning for doing this was unknown, but logical deduction pointed towards survival… perhaps they were protecting their homeworld, or maybe they were carnivorous and fed on other species.

Regardless, now that White had one in her sights she was going to find out. For science.

So, she kept her mouth shut during the meeting that was convened after Yellow’s corpse was discovered, allowing her crewmates to argue and point fingers at each other without interruption.

And despite the way Black seemed to fidget during the meeting, no one suspected him. What an oblivious bunch her comrades were; it was so _obvious._

But this time that worked in White's favor. As for her, this was an opportunity.

At the end of the meeting after the Captain ordered the rest of the crew to get back to their tasks, White lingered for a time; watching as Black loitered in the cafeteria before attempting to follow Red who had walked towards weapons alone.

… Now _that_ was blatantly and undoubtedly suspicious.

White thumped her fingers once against the table before standing and calling out to him, “Hey Black… before you get back to work, can you help me with something in the Medbay?”

Stopping dead in his tracks, his head snapped towards her almost unnaturally quick. “… The Medbay?” He paused only long enough to shrug before heading towards her. “Sure, I’m done with my tasks anyways so I’ll help with whatever you need.”

_Perfect._

This might be easier than she expected.

White waved her hand in a motion for him to follow before making a beeline to the destined location.

Now _,_ White knew that putting herself in an isolated room with a dangerous, predatory alien that probably wanted to murder her was a stupid idea. But the best scientific progress was made from taking risks.

The moment they were alone, she glanced at the lab bench before turning towards him. Smiling softly from behind her visor, she motioned to the scanner. _Better to confirm._ “I was hoping you’d help me inspect the blood samples, but it looks like they aren’t finished coagulating yet… how about you scan while we wait? According to your chart, it has been some time for you - you’re due.”

Black stiffened before relaxing again, speaking smoothly, “Really? You don’t see it? I could have sworn I scanned last week. I’d reckon a recordkeeping error.”

“I’m the one that maintains those records. Are you insinuating I made a mistake?”

“Uh, no! Of course not.” Black waved his hands in front of himself as though attempting to deflate a potential conflict. “I’m just _saying_ that it’s easy to overlook something like that, especially considering all the issues on the ship lately.”

White made a small ‘hrm’ before asking, “And what do you think about what’s been happening on the ship? You were rather quiet during the meeting this morning.”

“You were quiet too.” Black’s shoulders rolled into a shrug. “Someone dying is awful, but I didn’t see anything so I had nothing to say.”

“Didn’t see anything, huh? Even though you were _in_ the area when it happened?” White clicked her tongue before fixing her gaze firm on Black, a small bit of apprehension twisting her gut as she dropped the bomb: “… I know it’s you, Black.”

He froze. “… Know it’s me…? What do you mean?”

“Don’t play dumb; I know you were the one who killed Yellow. You’re not fooling me, Impostor.”

There was a sharp increase in tension in the air as she let her accusation simmer, so thick that it threatened to smother her lungs and made the hair on the back of her neck stand up…

And then she yelped when she was abruptly shoved against the wall, vision blurring and head throbbing as it knocked into the cold metal.

Blinking, she felt something coil around her wrists to keep them restrained, her sight clearing to find a mass of thick, oily-grey tentacles extending out of newly-formed, sharp-toothed maw in Black’s torso. A slamming sound echoed through the room, and her eyes darted towards the sole exit to see the door snap shut; trapping her inside the Medbay with him.

“And here I thought you were the _smart_ one,” Black hissed, the rounded surface of his helmet lingering dangerously close to hers and just barely allowing her to visualize a pair of glaring, yellow eyes behind it. “If you were so certain it was me, then _why_ did you wait until we were alone in a location I could so easily kill you to say so?” Another tendril slithered out of his suit, morphing into a sharpened state and lingering close to her chest in an idle threat to skewer her. “Please do tell me. The only reason you’re still alive right now is because I’m curious what you’re playing at.”

White swallowed before releasing a shaky breath, blood pounding through her ears as she tried her best to maintain her composure. She had never been known for her tact, so she counted herself lucky that he didn’t immediately kill her. But the shift in his demeanor was jarring: going from his usual shy and friendly self to someone cold and serious in a matter of seconds. Not to mention the blatantly inhuman tentacles that shifted and lurched against her body as though barely restraining themselves from ripping her to shreds.

Still, she held her head high and spoke calmly, “I had some questions for you I was hoping to discuss privately. Besides, if you killed me now the rest of the crew would know.”

He tensed. “You’re bluffing.”

“I’m not,” she assured. “You know how Green is: always watching those cameras. And you should also know that there’s one right outside of the Medbay. They recorded us coming in here together, so if I were to end up dead the same day… well, needless to say things wouldn’t turn out so great for you. Even the dumbest of crewmates could figure out that one.”

Black’s tentacles tightened around her limbs… before abruptly tearing away while he growled, “ _Fine._ What do you want?”

“Exactly what I said before: I have questions,” she stated while unclasping her helmet, letting her hair fall loose and setting it on the table.

Black’s gaze snapped between the helmet and her face while his tendrils halfway withdrew themselves into the ‘mouth’ in his torso. “Such as?”

“We’ll start with the obvious one – why are you here?” White asked as she sat down on one of the Medbay beds in an effort to appear disarming.

Black, on the other hand, remained standing while keeping his wary gaze on her. “… To get rid of intruders. We’ve seen what you’ve done to your home planet… we won’t take the risk of you doing that to ours.”

Snatching her notebook, she began to scribble in it while musing, “Survival. Just as expected.”

“Are you seriously writing this down?”

“Of course; this is for science. Next question – are you the only Impostor on board?”

“… Yes.”

“You’re not lying?”

Black let out a rigid snort. “Not this time.”

White hummed, tapping her pen against the notebook. “Okay, let’s move on. What happened to the real Black?”

“I killed him and assumed his form.” Black twitched before he too began to remove his helmet. He dropped it to the floor with a _thunk_ , revealing a human-like face that resembled the original Black outside of the slitted, wide-set eyes and sharp teeth.

Leaning forward, White squinted at him. “You look almost just like him, that’s fascinating… aside from the killing part of course. Can you do this with anyone? Why Black?”

“I can learn everything about another by assimilating them. Their appearance, thoughts, feelings… I found Black to be the most physically appealing out of all the males onboard, so I chose him.” His posture seemed to relax as his formerly neutral tone shifted to one more inquisitive, “… Doesn’t it bother you that I killed your crewmate?”

More scribbling. “Can’t say I’m happy about it, but what’s done is done and I understand why you felt it was necessary. So, thank you for being honest.” White looked up and gave a thorough once over of his figure. “You specifically said you chose a _male_ human. Is your base form male as well?”

Black canted his head. “It is… we have sexualities and reproduce in a way not too dissimilar to yours. Some Impostors don’t care about the form they take, whereas others like me have a preference.” There was a pause, then a sly grin spread over his face. “Why? … You interested in a demo?”

White blinked in surprise at his unexpected boldness, but still responded with a professional tone, “Are you implying you would mate with a human?”

“I can mate with any species whose form I take.” Black’s gaze narrowed into one more predatory before he strode over to her, tentacles extending outward and twitching around her body as he leaned in. “And when your own kind is dying out, you take opportunities whenever they arise.”

There was a jump in White’s heart rate at the sudden closeness… but she couldn’t tell if it was fear… or excitement. Perhaps a bit of both. She held her ground, gaze firm on him as she observed his next action.

He drew nearer so that he lingered less than a foot away, his cool breath brushing against her face. “… How about instead of these… _questions,_ we have a little fun, White? If you’re so curious about my biology, a live display might be more beneficial… and…” A tentacle traveled up to stroke her jawline. “… Maybe this could be our compromise instead of killing each other.”

A shiver ran down White’s spine as a shaky breath left her… but this time there were hints of curiosity mingling within the strange concoction of emotions. This Impostor wanted to… impregnate her? Create an alien-human offspring? He was dangerous but…

…

… But…

… This would be a good experiment for her research; groundbreaking really for a xenobiologist. 

_Fuck it, why not. For science._

A small grin played on her face. “… Maybe it could be.”

The notebook clattered to the floor and in the blink of an eye, she found herself flat on her back on the bed; Black straddling her and fiddling with the zippers to her suit. 

“Are you _sure?”_ he inquired while half-heartedly beginning to yank the suit off. “This means you’ll be bearing my spawn. Quite the commitment there.”

White merely laughed. It was kinder than expected of a murderous alien to double-check, but she already made up her mind. “I implied I wanted to, didn’t I? Let’s not dally like you do with your ‘tasks’.”

Black let out a small growl before increasing his efforts to remove her clothes tenfold, practically tearing them from her body before she had a chance to react further. They were tossed carelessly to the side and the next thing she knew, she was fully naked. The cool air of the Medbay bit her skin, distant chattering and mechanical sounds reminding her that her crewmates were still around working on tasks.

… Fortunately, Black was… _considerate_ enough to keep the Medbay door shut so no one would walk in on them.

A chill, slick sensation found White’s skin as his tentacles wrapped around her: one snaking up her abdomen and chest to toy with her breasts, while two others coiled around her thighs to spread her legs. He situated himself between them and cocked his head to get a good look at her, exhaling harshly.

Despite the way her cheeks burned and her skin shuddered at the sensation of his tendrils, she still teased, “What’s wrong? See something you aren’t used to?”

His gaze darted to her face. “No. I have your crewmate’s knowledge, remember?” he responded, smirking while squeezing her breasts. “But I have a hunch I’ll be giving _you_ something you’re not used to.”

White didn’t even get a chance to reply before she felt one of his smaller tentacles shift to worm its way inside of her, making her gasp and taking her breath away. It coiled inhumanely deep, oozing a thick liquid and exuding a foreign, slimy texture as it thrusted into her unprepared body. A shiver of surprised pleasure ran down her spine, spiking further and making her moan when the tentacles at her chest began to flick and twirl around her nipples.

Okay, he was right; this was most _definitely_ something she wasn’t used to. And now she was left wondering… how _did_ he actually reproduce? Did he have a cock...? Did he use his tentacles…? Was _this_ tentacle his reproductive device, or was it just foreplay…?

Either way, she supposed she would be finding out. And the pooling sensation in her gut informed that she certainly wasn’t disappointed.

“What an interesting human you are,” Black mused before licking his thumb and bringing it down to circle her clit, continuing to work his tentacles all the while. “I never imagined I’d find one not only willing to spare me when they found out, but also open to mating with me. Maybe not all of you are as bad as I thought.”

Though shuddering and letting soft moans tumble from her mouth, White still managed out, “W-we’d learn nothing about your kind if we j-just ejected you right away.”

“And yet you’re okay with the fact that I murdered Yellow and the real Black in cold blood.” Another tentacle slithered up her thigh to experimentally prod at her rear entrance.

“L-like I said before,” White gasped out as she was delivered an especially harsh thrust. “Casualties were expected on this mission… Plus, Yellow was kind of a dick. B-but!” She snatched his collar to drag him in close, dropping her tone to one more serious, “You have to agree to no more killing if I do this.”

White recognized that her morals were on the fence with choosing to spare an Impostor; most of her crewmates would oust and eject him without a second thought. But he had reasons for doing what he did, right? He just wanted to survive, like everyone else. Making amends would surely save more lives in the long run, along with the scientific benefits of keeping him around.

… Plus, he was starting to grow on her in other ways too… 

“Hmm…” Black grinned, baring his sharp teeth. “I suppose that’s fair. Deal.”

The moment he spoke the words the tentacle at her back entrance dove inside, beginning to thrust in rhythm with the other. It felt slick inside of her, allowing easy movement despite the lack of lube and somehow hitting her best spots each time. She parted her lips in a gasp…

… And was promptly smothered by Black crashing his mouth against hers, tongue prodding its way inside. She parted her lips further, curiously stroking her own tongue over his sharp fangs before working it against his. He tasted… just like a normal human. Huh. His tongue was definitely longer though.

Continuing to work against him, her hands raked through his dark hair before wandering down his still-clothed figure to experimentally pump one of the tendrils. He let out a low groan in response, his tentacles shivering against her body.

Breaking the kiss and pulling back, he huffed out, “… I admit I’ve had my eyes on you for a while. Despite my earlier threat, killing you would have been pretty hard.” A low chuckle left him as he drew his tongue up her neck. “I’m actually quite alright with this turn of events."

Another shiver coursed down her spine when his fanged teeth nibbled at her earlobe, followed by a languid moan as he continued to jerk his tentacles into her. “Hah-hah,” she shuddered out. “The feeling’s mutual.”

He cocked his head, observing her with an overly satisfied grin. “… It’s also pretty cute to see you lose your composure like this. The proud and serious White, dragged down to a moaning mess.”

“C-careful now… let’s not forget who holds the cards here!” White warned through her pants, trembling as that pressure in her gut crept close to overflowing.

Black snorted out a short laugh. “Still on about that? I’m hurt you’d have them eject me over a little teasing.”

“ _Nooo,_ b-but you have torn people in two like it’s nothing! I know what you’re capable of!”

“Well, yeah, but I’m not gonna anymore.”

“… D-do, hah, all Impostors fuck around this much when doing the deed? Ooor is this just a personal thing?”

At her remark, Black yanked his tentacles from her holes. He then proceeded to stroke the length of one along her entrance and clit, making her shudder and hold her breath; her gut clenching in torturous anticipation of impending climax that was just barely being kept at bay. All the while his other tendrils continued to fondle various parts of her body: some snaking around her limbs and abdomen, and others massaging her chest as though he was obsessed with touching her.

“And here I thought humans liked foreplay,” he drawled while beginning to fiddle with the crotch to his suit and all but ignoring the rest of her question.

White opened her mouth to retort… but found her words swiftly snuffed out as that pressure in her gut spiked to its breaking point, making her clench her teeth and spasm as she was sent rocketing into the release of orgasm.

When the moment of pure bliss passed, she was left panting on the bed with trembling muscles as she recovered. She blinked and attempted to refocus on Black through arousal-hazed vision, noticing that the crotch of his suit was now opened to expose a dripping, mottled-grey, writhing cock.

Oh… _oh…_ it was… definitely bigger than she expected. Much larger than the tentacles that were inside her before. But Black wasn’t human, so she shouldn’t be so surprised.

Hell, she was excited.

The second her widened eyes returned to his face, his mouth twitched into a smug grin and his cock slithered in to press against her slickened entrance. Biting her lower lip, she arched her back to allow better access, readying herself for his penetration…

… Then he pulled away, forcing a whimper to slip out at the loss of contact. His tentacles tightened around her body, and moments later she found herself flipped onto her stomach before being pulled to her knees by the tentacle wrapped around her abdomen.

She wasn’t prepared for the sudden change in position. Maybe this was the preferred for his species? Or perhaps just the preferred for him as an individual. Either way, the throbbing at her core told her that she was getting _antsy_. She _needed_ this. 

Again, she felt him brush against her from behind, his writhing cockhead pushing slightly and squirming against her entrance… but never quite penetrating her. Another whimper left her, and she definitely would have taken the initiative herself were his tentacles not wrapped around her abdomen and limbs to secure her in place.

_Come on!_

He… he was teasing her, wasn’t he?

Black gripped her hips, rubbing against her as he leaned over her from behind to whisper, “Ready?”

“ _Fuck!_ Yes,” White hissed, trying to remain somewhat quiet as her body screamed internally in desperation. “Just get on with it already!”

That was all the prompting Black need to dive inside of her, the tentacle-like cock stretching and filling her entirely. And as though exaggeratingly complying with her demand, he wasted no time before beginning to piston into her.

“So impatient. All you had to do was ask,” he taunted, panting in-between words while he worked his hips.

She gasped at the sensation; the scent of her renewed arousal thick in the air as he managed to get that perfect angle with each thrust. It felt different yet similar from his other tentacles, firmer and definitely thicker but still flexible… And good, it also felt so very _good._

In fact, this might just be better than being with another human.

In no time at all, she once more found that pressure in her abdomen winding up and drawing close to climax, making her grow suspicious that there was some kind of aphrodisiac exuding from him. She had never orgasmed this fast in such a short amount of time before.

… Was that a thing…? Aphrodisiac pheromones…? Or perhaps they were in that fluid leaking from his tentacles; intradermal absorption was a possibility.

White supposed it could be anything with an unknown alien species. She would have to quiz him more on that later…

…

… Or… maybe just do more hands-on experimentation. For science of course.

She yelped when one of the smaller tentacles returned to press into her rear entrance, diving inhumanly deep as it thrusted in rhythm with the other. Again, she shuddered, breath hitching as her abdominal muscles tensed, like a taut string ready to _snap…_

_… Just a little bit more._

Black let out a lengthy groan from on top of her, his tentacles quivering and his breaths turning ragged. Out of the corner of her eyes, White could see him open his mouth as though intending to say something… before closing it in favor of thrusting more feverously.

He must be getting close too.

It only took a few more jerks to send White plummeting into another wonderous orgasm, her walls squeezing his tentacles as they continued to pump into her through it all. The overstimulation shot a fog of arousal straight to her head, leaving her feeling numb while specks of black mottled her vision.

Black followed soon after, burying himself as deep as he possibly could before letting out a low groan as a pool of warmth filled her gut.

With a sigh, he pulled out, his tentacles retreating back inside of him and the ‘mouth’ in his chest snapping shut; reverting back to his more human-like form. He crashed next to her on the bed and muttered, “Damn. That was better than I thought.”

White laughed through her panting, staring up at the fluorescent overhanging light of the Medbay. “Hah, glad I didn't disappoint. Aaand I concede that you’re right - I’ve never had anything like it before.”

Black merely gave a hum of approval.

“What’s the success rate of conception for your species?” she asked. That was the original goal of this, after all. White would be a poor researcher to lose sight of that… not to mention the fluid actively seeping from her acting as a blatant reminder.

“Mmm, dunno. It varies. We can always try again if you’re up for it.”

“That could be arranged… as long as our truce still stands.”

A low chuckle reverberated from Black as he extended his hand out. “I know my kind doesn’t have a great track record for being honest, but I’m an Impostor of my word. I’ll even shake on it.”

“You’re a terrible liar anyways. I’d know if you were,” White joked before grasping his hand to squeeze it.

“Uh huh. Round two tomorrow, same time and place?”

“It’s a date.”

Yes, for White, this was the opportunity of a lifetime. 

_For science._


End file.
